Jenna Dudevoir, global vice president of marketing for Kalypso, a worldwide consulting firm with offices in Boston, posted an opening for a paid internship last year. One applicant’s resume seemed strong. But before scheduling an interview, Dudevoir took a look at his Twitter feed.

“I was appalled,” she recalls. “It was laced with profanities and sexist remarks. I threw his resume in the trash.”

Nearly 80 percent of employers research job applicants on the Internet, and 70 percent have rejected candidates because of their online profile, according to a recent Microsoft survey.

For many job-seeking college seniors, cleaning up their online persona has become a must. But that can be a major undertaking, including not just their own posts on a variety of sites but embarrassing tidbits posted about them by friends or acquaintances.

Get The Weekender in your inbox:

The Globe's top picks for what to see and do each weekend, in Boston and beyond.

“Many students have been comfortable with the intimate details of their lives on display since birth, so they may not have considered the ramifications of their spring break pictures or other posts that may seem unprofessional,” says Lisa Severy, of the National Career Development Association, whose members include campus career counselors.

Todd Van Hoosear, who teaches public relations at Boston University and has long been advising students about using social media wisely, heard about a Boston law firm preparing to hire a young law school grad. But instead of a six-figure job offer, she was confronted with a Facebook picture posted by a friend and discovered during an online search. It had been snapped at a party she’d attended where illegal drugs were present — and visible. The young woman promised to have the photo taken down.

Horror stories like these, according to Severy and others, show that even if students pay attention to their own profiles, removing or hiding content that might come back to haunt them, they may not realize their friends’ postings can damage them, too.

“People often think about their own pages, but not pages they may be tagged to on other people’s profiles,” Severy notes.

Severy and others say the best strategy is building a more professional-looking profile, using a site like LinkedIn, that will surface high in any online search by a potential employer. Hiding less flattering material is not always easy, they note, although there are services that can help — some launched by college students themselves.

One is Brand-Yourself.com, an Internet reputation management service created by a group of Syracuse University students. Their do-it-yourself digital platform uses search engine optimization, a process that influences how Web pages are ranked, to bury negative information and elevate positive material, such as a person’s LinkedIn account. The product itself is free, although premium services cost a few dollars a month.

About a month ago, a Kent State University student group launched SimpleWash, a free app (simplewa.sh) that searches out objectional Facebook material — including comments posted by others — using a precompiled or customized word list. Once identified, this material can either be deleted or hidden behind privacy settings.

“We’re not advocating lying about who you are. It’s more like, hey, I was young once,” says cofounder David Steinberg, a Kent State senior, whose site has already collected more than 200,000 unique views. The app’s main aim, he says, is to ease the transition between college and the working world, at a time when some employers are going so far as to ask job applicants for their log-on information. Rather than deactivating their Facebook pages, SimpleWash users can clean them up and make them more presentable.

Brandeis University senior Erica Shaps, 21, works part time at the university’s Hiatt Career Center, advising fellow students on social media strategy and steering them toward workshops like managing your brand in the digital age. She encourages seniors to undertake online cleanups when necessary but focuses on helping them build their professional networking pages.

Besides receiving the usual Facebook warnings — don’t post anything you don’t want a parent or employer to see — many students are debating whether to untag or delete older, questionable material, according to Shaps.

For the most part, students take care of these problems themselves, she says. “My generation has an innate understanding of how Facebook works. They know how to untag and remove stuff, and how to reset privacy settings.”

Some students take the further step of changing their Facebook pages to first-name only, she adds, or inserting a space between first and last names, to further complicate the search process.

Others, like BU senior Stephanie Madison, 21, have simply abandoned old habits that could jeopardize job prospects. As a freshman, Madison, who hopes to land a job in sports operations, tweeted plenty of stuff she is not proud of today.

“It was a lot of dumb things, commenting on literally anything I was doing,” she says. “And I cursed a lot,” which she no longer does on Twitter.

To help its students put their best faces forward, Boston College’s career center conducts workshops on online profile-building. At campus jobs fairs, it sets up photo booths where students can have their portraits taken, shots suitable for posting on professional networking sites.

“The more positive stuff you input, the more it pushes the negative down,” says Louis Gaglini, the center’s associate director of employer relations.

Northeastern University’s career services office offers weekly workshops in both basic and advanced LinkedIn site-building, accommodating 20 students per session. Students are also counseled to change their Facebook privacy and security settings, to ensure that more personal material is hard to access.

Even for universities helping students navigate the job search and social media landscapes, though, staying on top of technology can be challenging.

“The next generation may not be using Facebook so much” as other options become available, says NU career services director Maria Stein.

Over at BU, social media active professors like Van Hoosear and Stephen Quigley are laying down basic rules for students to follow.

One is, don’t lie about your resume or references. Also, avoid taking sole credit for a team’s accomplishments, especially when job prospecting in a field like public relations, where firms value collaborators over ego-driven “me first”-ers. Third, don’t come across as “too vanilla” if you’re aiming for a creative field like advertising. There’s a difference, they say, between looking wild and crazy on Facebook and looking so bland that no personality-driven firm will want to hire you.

BU senior Ben Heyman, a public relations major soon to be job hunting, has taken such advice to heart. “I used to share some pretty stupid stuff, like what I had for lunch,” admits Heyman, 21, who’s gone back and deleted some postings he was uncomfortable with. “Now I tweet more about stuff I’m interested in and others might be, like articles, blogposts, and company brands.”